>>1080>I got confused because certain things can be omitted if they're implied by context.
For some reason everybody fails to explain why context is important in japanese without making it sound like some sort of esoteric concept that requires extremely deep understanding of the mechanics of the language or something. It's actually fairly simple. It's not that you have to omit things every single time, it's just that certain things are assumed to be obvious and thus implied instead of being stated. These mostly have to do with the subject of a sentence, as you point out. By default (if no subject is specified), it's usually the first person. But if it's not about the subject, it will still be obvious and not some abstract thing that requires you to read books or something.
食べる -> I [will] eat (something).
食べる？ -> [Me?] Eat this?
食べない -> will not eat
But you can change "I" and "me" for any other subject and they still work, provided it's obvious from context (not omitted because of some magical force). Let's just do this now: I'm going to inject some context. You're in my house and I tell you "feel free to eat some grub". After some consideration, you say "okay, I will eat".
Me: りんごを食べていいよ。"You can eat apples if you want."
You: なら、食べる。"Okay, I'll eat".
Now, let's change the scenario a bit. Suppose you bought some exotic crap and I'm just puzzled how somebody could dig that shit.
You:昨日、市場でこの食べ物を買ったよ。"Yesterday, I bought this food on the market".
Me:ええぇ、これ、食べる？ "Huh? can you even eat this?"
Now, let's change the words on this scenario little.
You:昨日、市場でこの食べ物を買ったよ。食べてみたい？ "Yesterday, I bought this food on the market. Want to eat some?"
Then I put an extremely disgusted face. The tones in my voice are sharp and short as I speak.
Me:食べる？動物か？食べないんだよ。 "Me? eat this? Am I an animal or something? I'm not eating this crap."
Then we hear noises coming from next room.
You: お姉さんだ。帰ってたって知らなかったよ。多分疲れてる。今、呼んでいく。 "It's my sister. Didn't know she had come house. She must be tired, I'll go call her."
Me:食べさせるのか？ "Are you going to make her eat this?"
You:いや、もう食べたと思う。"Nah, she probably has had something to eat already".
Notice onee-san was mentioned only once throughout the conversation. In fact, the "default" subject (1st person) from that point onward is shifted to "onee-san", thus she becomes the default subject. We don't even specify who's the subject anymore just because it's obvious, just not stated. Et cetera, it's fairly simple once you get used to it.
———>You can just say [名前]です without 私は, unlike in english
You are confusing は for "is" in english. The verb "to be" is, by default, implied in japanese. The polite way of stating it is です, while だ accomplishes the same role for informal japanese. But です is NOT the polite version of だ (the proof being that you can use です in questions but not だ).
>学生 -> [A] student. / [Subject] is student (odd to use but valid)>学生だ -> [subject] is student.>学生です ->[subject] is student. (polite)
The three are exactly the same and mean the same. は only introduces the topic. I believe Tae Kim likes to translate は like this: "As for…"
私は[名前]です -> "[As for me], I'm [name]".
"That doesn't make any sense!", you may think, but you have to remember は introduces topics, and thus is used virtually anywhere in the sentence if there's a noun (or a nominalized sentence) behind it.
昨日はラメんが食べたんだ。 "I ate ramen yesterday". Or tae kim version: "[As for/speaking about] yesterday, ate ramen".
It takes a little to get used to it but always thing of は as introducing the topic; an arrow with lights and whistles with a sign saying "THIS IS THE TOPIC".
>Following that rule, within your scenario it would just be implied that you're asking what the noise is, but apparently not.
Ah, that example is a hard one because it requires more information to have a real meaning. すごい音ですか？ by itself means "is it a very loud sound?". If you are telling me you love the sound of the turbines of a plane, I may ask "すごい音ですか？" (is it really that loud?) and it's just perfect. Or, following my own example, if you tell me your kitchen exploded yesterday, I may ask "すごい音でしたか？" (It was really loud, wasn't it?).